Stackable boxlike containers provided with interlocking means



R. THEOBALD Oct. 20, 1970 STACKABLE BOXLIKE CONTAINERS PROVIDED WITH INTERLOCKING MEANS Filed July 5. 1968 In ventar: PEI/VER 79 505910 Oct. 20, 1970 R. THEOBALD 3,534,335

STACKABLE BOXLIKE CONTAINERS PROVIDED WITH INTERLOCKING MEANS Filed July 5, 1968 4 9 Fig.2 3 (V 6 \w Fig.5

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In ventor: FEM/5F 76 605/91 D 2 Sheets-$heet 2 United States Patent Int. Cl. B65d 21 /02 US. Cl. 220-97 5 Claims ABSTRACT OF THE DISCLOSURE An effective interlock is provided between boxes to be stacked without relying on openings which would weaken the walls and reinforcing ribs. At least one of the side faces is provided with at least one additional rib extending at an angle to a similar rib of a similar face of a further similar box. Said additional ribs are interrupted about at their centers to form two rib sections each, and the two rib sections of each of said additional ribs are transversely offset by an amount which is at least equal to the thickness of the rib, to interengage when the side walls of different boxes are forced against each other.

This invention relates to interlocking means provided on stackable boxlike containers, which consist preferably of plastics material. Such boxes serve mainly as boxes for handling food, such as fruit, or bottled beverages. In the handling of wine bottles, e.g., it is important that the boxes of plastics material should be stacked so that the opening faces laterally and the bottles can be removed at any time from each box of a stack. Such stacks of boxlike containers having laterally facing openings are generally required when the contents should be kept in the boxes in a horizontal position. The stacking of the boxes with laterally facing openings enables an assembling of shelves, which may be used in stores as well as in basements of private homes. It is also often desirable to prevent a shifting of these boxes relative to each other when the boxes are being handled.

Boxes for bottles are known, which are provided with a locking device to facilitate the stacking of the boxes with a laterally facing opening. Each of these boxes for bottles is provided with two ribs, which extend on the sides at right angles to the grip rim. One of these ribs is offset from the other by at least one wall thickness so that the opposite rib of the next box can enter the free space between the ribs of the underlying box. In a similar box, the ribs and pairs of ribs are aligned. These boxes are relatively simple but have the disadvantage that the spaces between the ribs cannot be found quickly enough when the boxes are being stacked so that they are often missed. This has undesirable results particularly if the contents of the boxes are heavy. A wrong placing of the boxes often causes the entire stack to collapse. Besides, said interlocking means are not sufficient in many cases to hold the boxes in their desired position during stacking. As with the first-mentioned design, the lower box rests only on longitudinal ribs so that the entire stack may swing laterally. This can have undesirable results particularly with heavy loads. Finally, an embodiment is known in which the desired overlap is provided by the provision of ribs which extend at right angles to the rim of the box and enter recesses of the reinforcing ribs which extend parallel to the rim of the box. This design does not, however, eliminate the abovementioned disadvantages. Besides, the recesses substantially reduce the stability of the box so that the reinforcing ribs do not fulfill their intended function.

Patented Oct. 20, 1970 'ice To impart a high inherent stability to the stack which has been described first and in order to avoid the abovedescribed disadvantages, it is an object of the invention to provide suitable interlocking means for boxes of plastics material, which interlocking means are firmly provided on each box and are designed to have a self-adjusting action during stacking so that the interlock is accomplished only by a correct stacking in any desired attitude of the main dimensions of the box.

To accomplish this object, and to provide further advantages a stackable boxlike container is proposed by the invention which comprises a rim which defines an opening, mutually opposite side walls having outside surfaces, reinforcing ribs provided on said outside surfaces and extending generally parallel to said rim, and at least one additional rib provided on at least one of said outside surfaces extending at an angle to a similar rib of a similar outside surface of a further similar boxlike container, said additional ribs being interrupted about at its center each to form two rib sections, and the two rib sections of each of said additional ribs are transversely offset by an amount which is at least equal to the thickness of the rib. The additional ribs are fixing elements which are integrally comolded with the box if the same consists of plastics material. The additional ribs will impart a reliable inherent stability to the stack even if they protrude only slightly from the plane of the side face of the container. Within the scope of the invention it will be desirable if the diagonal ribs continuously taper in height from the outside toward the center. With ribs of this design, the containers will lock themselves in position when they are being stacked because the fixing elements contacting each other will automatically adjust themselves under the action of their inwardly inclined surfaces. Even when the containers have not been superimposed in a correct position, a slight shaking will be sufficient to effect an exact mutual adjustment of the fixing elements. Further this invention has the advantage that both fixing elements in the corner regions may have almost the same design. It is also desirable in this connection to provide rib parts which are stiffened or reinforced by transverse webs.

The invention is illustrated in the drawings.

FIG. 1 shows two boxlike containers, which are stacked one on the other. The interlocking means according to the invention are provided in the forward corner regions of the lower container and are designed as shown in FIG. 4. Modified interlocking means are shown in FIGS. 2, 3, 5 and 6.

As is apparent from FIG. 1, two interlocking means are provided in these corner regions of the side faces which are adjacent to the container opening 1 of the container 2. The simplest solution of this kind is apparent from FIG. 2, where two diagonal ribs 3 and 4 are shown. One of these ribs, namely, the diagonal rib 3, is centrally interrupted to receive the non-interrupted diagonal rib of the adjacent container being stacked. As is apparent from FIG. 3, both diagonal ribs 5 and 6 are interrupted at their center in another embodiment of the invention. Both rib sections are transversely offset to an extent which is equal to their thickness, and are provided with supporting ribs. An embodiment without supporting ribs is shown in FIG. 4, which indicates also how the diagonal ribs coact during stacking. The two embodiments shown in FIGS. 5 and 6 operate on the same principle. In this connection it is mentioned that the inwardly directed edges of the interlocking elements 7 and 8 may be rounded.

What is claimed is:

1. A stackable boxlike container comprising opposite side walls having outside surfaces, a rim around said walls, reinforcing ribs on said outside surfaces spaced from and parallel to said rim and intersecting adjacent the-comers of said surfaces to form recesses, an additional rib in each recess interrupted at its center to form two rib sections transversely offset by an amount at least equal to the thickness of said rib, and said rib sections being projected beyond said rim and extending at an angle with respect to corresponding ribs on an adjacent container for forming a four-point contact between the free ends of said rib sections when such containers are stacked.

2. A stackable boxlike container as set forth in claim 1, in which said additional ribs continuously taper in 10 1, which consists of plastics material and in which said additional ribs are integrally comolded with said side walls.

5. A stackable boxlike container as set forth in claim 1, in which said additional ribs extend at right angles to each other.

References Cited UNITED STATES PATENTS 3,353,703 11/1967 Bartoo 22O21 FOREIGN PATENTS 1,196,118 7/1965 Germany.

662,034 4/1964 Italy.

4. A stackable boxlike container as set forth in claim 15 GEORGE E. LOWRANCE, Primary Examiner 

